Algorithm

  1. Input:

    • Accept the input string.
    • Accept the desired starting and ending characters.

  2. Validation:

    • Ensure that the input string and the specified starting and ending characters are not empty.

  3. Check Starting Characters:

    • Extract the substring from the beginning of the input string with a length equal to the length of the starting characters.
    • Compare this substring with the specified starting characters.
    • If they match, continue to the next step; otherwise, the string does not start with the specified characters.

  4. Check Ending Characters:

    • Extract the substring from the end of the input string with a length equal to the length of the ending characters.
    • Compare this substring with the specified ending characters.
    • If they match, the string starts and ends with the specified characters; otherwise, it doesn't.

  5. Output:

    • Display a message indicating whether the string starts and ends with the specified characters.

 

Code Examples

#1 Code Example- Check String Using Built-in Methods

Code - Javascript Programming

// program to check if a string starts with 'S' and ends with 'G'

function checkString(str) {

    // check if the string starts with S and ends with G
    if(str.startsWith('S') && str.endsWith('G')) {
        console.log('The string starts with S and ends with G');
    }
    else if(str.startsWith('S')) {
        console.log('The string starts with S but does not end with G');
    }
     else if(str.endsWith('G')) {
        console.log('The string starts does not with S but end with G');
    }
    else {
        console.log('The string does not start with S and does not end with G');
    }
}


// take input
let string = prompt('Enter a string: ');
checkString(string);
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Output

x
–
+
cmd
Enter a string: String
The string starts with S but does not end with G

#2 Code Example- Check The String Using Regex

Code - Javascript Programming

// program to check if a string starts with 'S' and ends with 'G'

function checkString(str) {

    // check if the string starts with S and ends with G
    if( /^S/i.test(str) && /G$/i.test(str)) {
        console.log('The string starts with S and ends with G');
    }
    else if(/^S/i.test(str)) {
        console.log('The string starts with S but does not ends with G');
    }
     else if(/G$/i.test(str)) {
        console.log('The string starts does not with S but ends with G');
    }
    else {
        console.log('The string does not start with S and does not end with G');
    }
}

// for loop to show different scenario
for (let i = 0; i < 3; i++) {

    // take input
    const string = prompt('Enter a string: ');

    checkString(string>;
}
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Output

x
–
+
cmd
Enter a string: String
The string starts with S and ends with G
Enter a string: string
The string starts with S and ends with G
Enter a string: JavaScript
The string does not start with S and does not end with G
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Demonstration

JavaScript Programing Example to Check Whether a String Starts and Ends With Certain Characters-DevsEnv

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